Globally, over 500 million people are obese, and bariatric surgery represents the only effective long-term treatment. Binge eating disorder (BED) is the most common psychiatric disorder in bariatric surgery candidates and may have an impact on surgical outcome. BED is characterized by consumption of an unusually large amount of food with loss of control, without compensatory behaviors (e.g., vomiting). Binge foods usually consist of high-palatability foods (HPF), such as ice cream and pizza. Engaging in binge eating behavior may be indicative of underlying disordered neural mechanisms. Two studies showed that BED individuals have greater brain activation in response to HPF than nonBED individuals. Although roux-en-Y gastric bypass (RYGB) has recently been shown to reduce brain activation in response to HPF in nonBED, it is unknown whether there would be a reduction in BED. We propose that BED individuals will show similar reductions in brain activation as nonBED after RYGB, but that BED individuals will continue to have relatively greater brain activation due to disordered neural mechanisms. This study will use functional magnetic resonance imaging (fMRI) and eating- related questionnaires to examine the neurobiological and behavioral aspects of BED in the RYGB population under the umbrella of a larger NIH funded project, Functional Brain Imaging and Appetite-Related Hormones Pre and Post Obesity Surgery (Geliebter: PI). Participants undergoing RYGB will be compared to those who qualify for, but choose not to undergo surgery and receive no treatment (NT). Participants will be studied at pre-surgery (baseline), 3 months post, and 1 year post baseline. Differentiated from the parent study, this study (1) compares BED with nonBED, 2) adds the Power of Food Scale (PFS) and the Emotional Appetite Questionnaire (EMAQ), (3) examines additional brain reward regions of interestthe medial orbitofrontal cortex, ventral tegmental area, and ventral striatum, (4) adds a 1 yr follow-up for questionnaires and weigh- in, (5) adds five covariates, including living environment, race, ethnicity, marital status, and income. PFS and the EMAQ will be administered, and fMRI will be used to examine areas of brain activation in response to visual stimuli of HPF, low-palatability foods (LPF), and non-foods (NF). Sixty-eight relatively healthy (non- diabetic) severely obese (BMI = 40-50 kg/m2) men and women will be enrolled, with 34 (17 BED, 17 non-BED) in each group. Groups will be matched for gender and BMI. Findings should improve knowledge of the mechanisms that contribute to BED, and the interaction of BED with RYGB. This knowledge may lead to new clinical assessments and adjunct treatments for BED individuals who are candidates for RYGB. With this F31, I will (1) obtain a solid foundation in the current theories and models of neuroscience, (2) become proficient in the various technical, statistical, and computational aspects of neuroimaging data analysis, and (3) publish and present at national and international conferences, with the objective of advancing clinical treatments in BED. This training will prepare me for a productive research career as an independently funded NIMH investigator.